1. Field of the Invention
The present invention relates to a method of establishing connections between at least two communication terminals in order to run an application requiring the exchange of data between said terminals. As an example, the present invention relates to interactive applications, in particular, of the multimedia type.
To the purpose of the present invention by the expression “interactive application running between two or more terminals” it is meant an application, typically a software application, wherein at each terminal a transition from an application status to another application status is also dependent on data received by another terminal.
To the purpose of the present by the expression multimedia application it is meant an application in which are involved any combination of two or more of the following elements: text, image, sound, speech, video and software.
2. Description of the Related Art
Examples of known interactive multi-media applications are on interactive multimedia gaming, video conference, telepresence (i.e. an application requiring high definition video communications and acquisition of images by a video camera). Normally the users of such applications are provided with terminals (for both fixed and mobile access) comprising a local elaborating device (for example, a personal computer or elaborating functions inside a cellular device) connected to peripheral equipments such as a game console, a high definition TV for tele-presence and/or a video-camera. The local elaborating device allows to run the application in executing a specific software.
According to known technologies, the user terminal can be connected by means of a communication network to a further user terminal assigned to another user. As an example, for connecting the terminals involved in interactive multi-media applications are employed the following conventional communication networks: circuit-switched networks (operating, for example, according to a Time Division Multiplexing technique, TDM) or packet-switched networks (operating, for example, according an Internet Protocol, IP). The connection of the user terminals to the network is normally performed by a fixed access network (e.g. dial-up, Digital Subscriber Line DSL, cable) and/or mobile and/or nomadic access network (e.g. Wireless Fidelity WiFi, World Wide Interoperability for Microwave Access WiMax, Global System for Mobile Communications GSM, General Packet Radio Service GPRS, Universal Mobile Telecommunications System UMTS).
The exchange of data between the two user terminals (such as the exchange of digital images in a video-conference), associated with the running of the multimedia interactive application, can occur only when the network has established a suitable connection between the two terminals and the applications are available for exchanging data. This connection can be established when the networks elements (e.g. access nodes or the core network) are available to provide their resources for the connection to be established.
Document U.S. Pat. No. 6,765,918 describes a method for establishing a connection in a telecommunication network that provides allocation of bandwidth to carry voice, data and video signals between users and the network. The network comprises a plurality of multimedia channel banks connected to users equipments including telephones, computers, set-top boxes, apparatus for producing video signals. The network is also provided with a multimedia resource manager acting as real time proxy and resource manager capable of responding to several trigger i.e. script, network signaling, end-user signaling.
Document US-A-2002-0114274 discloses a packet-based network providing interactive voice, video and multimedia applications. This network includes a backbone network, a network server, access or edge routers and local servers. This document describes a method for setting up a session according to which a local server receives a request for service and, according to an example, requests access from the backbone network. The network server resolves the destination IP (Internet Protocol) address and receives access confirmation. Subsequently to the access confirmation, the set up of the application is carried out by means of a Session Initiation Protocol, SIP. The SIP protocol is a known terminal-based signaling protocol.
Document WO-A-02-44919 describes an IP communication network coupled to equipments of a number of customers. The network is provided with a core communication links, customer routers and a network access system that distributes the function of traditional edge routers between three logical modules: a programmable access device, an external processor and an access router. The external processor performs, inter alia, the signaling to set up and tear down access network connections. This document illustrates a network-level signaling utilizing the known Resource Reservation Protocol (RSVP) and an application-level signaling using the above mentioned SIP.